//! # 框架核心实现
//! 
//! 本模块提供了RustCloud框架的核心实现，负责管理所有微服务组件的生命周期。

use crate::config::RustCloudConfig;
use crate::framework::traits::*;
use rustcloud_core::{ServiceResult, ServiceError, ServiceInstance};
use rustcloud_registry::ServiceRegistry;
use rustcloud_loadbalancer::LoadBalancerStrategy;
use rustcloud_circuit_breaker::CircuitBreaker;
use rustcloud_metrics::MetricsCollector;
use std::sync::Arc;
use std::collections::HashMap;
use tokio::sync::RwLock;
use tracing::{info, warn, error};

/// RustCloud框架主入口
/// 
/// 负责管理所有微服务组件的生命周期，提供统一的服务接口
pub struct RustCloudFramework {
    /// 框架配置
    config: RustCloudConfig,
    
    /// 服务注册中心
    registry: Arc<dyn ServiceRegistry>,
    
    /// 负载均衡器
    load_balancer: Arc<dyn LoadBalancerStrategy>,
    
    /// 熔断器（可选）
    circuit_breaker: Option<Arc<CircuitBreaker>>,
    
    /// 指标收集器（可选）
    metrics_collector: Option<Arc<dyn MetricsCollector>>,
    
    /// 自定义组件
    custom_components: HashMap<String, Box<dyn std::any::Any + Send + Sync>>,
    
    /// 服务实例信息
    service_instance: ServiceInstance,
    
    /// 框架状态
    state: Arc<RwLock<FrameworkState>>,
    
    /// 生命周期管理器
    lifecycle_manager: LifecycleManager,
}

/// 生命周期管理器
pub struct LifecycleManager {
    /// 启动钩子
    startup_hooks: Vec<Box<dyn Fn() -> ServiceResult<()> + Send + Sync>>,
    
    /// 关闭钩子
    shutdown_hooks: Vec<Box<dyn Fn() -> ServiceResult<()> + Send + Sync>>,
    
    /// 健康检查处理器
    health_check_handlers: Vec<Box<dyn Fn() -> ServiceResult<bool> + Send + Sync>>,
}

impl Default for LifecycleManager {
    fn default() -> Self {
        Self {
            startup_hooks: Vec::new(),
            shutdown_hooks: Vec::new(),
            health_check_handlers: Vec::new(),
        }
    }
}

impl LifecycleManager {
    /// 添加启动钩子
    pub fn add_startup_hook<F>(&mut self, hook: F)
    where
        F: Fn() -> ServiceResult<()> + Send + Sync + 'static,
    {
        self.startup_hooks.push(Box::new(hook));
    }

    /// 添加关闭钩子
    pub fn add_shutdown_hook<F>(&mut self, hook: F)
    where
        F: Fn() -> ServiceResult<()> + Send + Sync + 'static,
    {
        self.shutdown_hooks.push(Box::new(hook));
    }

    /// 添加健康检查处理器
    pub fn add_health_check_handler<F>(&mut self, handler: F)
    where
        F: Fn() -> ServiceResult<bool> + Send + Sync + 'static,
    {
        self.health_check_handlers.push(Box::new(handler));
    }

    /// 执行启动钩子
    async fn execute_startup_hooks(&self) -> ServiceResult<()> {
        for hook in &self.startup_hooks {
            hook()?;
        }
        Ok(())
    }

    /// 执行关闭钩子
    async fn execute_shutdown_hooks(&self) -> ServiceResult<()> {
        for hook in &self.shutdown_hooks {
            hook()?;
        }
        Ok(())
    }

    /// 执行健康检查
    async fn execute_health_checks(&self) -> ServiceResult<bool> {
        for handler in &self.health_check_handlers {
            if !handler()? {
                return Ok(false);
            }
        }
        Ok(true)
    }
}

impl RustCloudFramework {
    /// 创建新的框架实例
    pub async fn new(
        config: RustCloudConfig,
        registry: Arc<dyn ServiceRegistry>,
        load_balancer: Arc<dyn LoadBalancerStrategy>,
        circuit_breaker: Option<Arc<CircuitBreaker>>,
        metrics_collector: Option<Arc<dyn MetricsCollector>>,
        custom_components: HashMap<String, Box<dyn std::any::Any + Send + Sync>>,
    ) -> ServiceResult<Self> {
        // 创建服务实例信息
        let service_instance = ServiceInstance {
            id: config.service.instance_id.clone()
                .unwrap_or_else(|| uuid::Uuid::new_v4().to_string()),
            name: config.service.name.clone(),
            version: config.service.version.clone(),
            host: "localhost".to_string(), // TODO: 获取实际主机地址
            port: config.network.port,
            metadata: config.service.tags.clone(),
            health_check_url: Some(format!("http://localhost:{}/health", config.network.health_port)),
            weight: 1,
            enabled: true,
        };

        let framework = Self {
            config,
            registry,
            load_balancer,
            circuit_breaker,
            metrics_collector,
            custom_components,
            service_instance,
            state: Arc::new(RwLock::new(FrameworkState::Uninitialized)),
            lifecycle_manager: LifecycleManager::default(),
        };

        Ok(framework)
    }

    /// 获取服务实例信息
    pub fn get_service_instance(&self) -> &ServiceInstance {
        &self.service_instance
    }

    /// 获取配置
    pub fn get_config(&self) -> &RustCloudConfig {
        &self.config
    }

    /// 获取注册中心
    pub fn get_registry(&self) -> Arc<dyn ServiceRegistry> {
        self.registry.clone()
    }

    /// 获取负载均衡器
    pub fn get_load_balancer(&self) -> Arc<dyn LoadBalancerStrategy> {
        self.load_balancer.clone()
    }

    /// 获取熔断器
    pub fn get_circuit_breaker(&self) -> Option<Arc<CircuitBreaker>> {
        self.circuit_breaker.clone()
    }

    /// 获取指标收集器
    pub fn get_metrics_collector(&self) -> Option<Arc<dyn MetricsCollector>> {
        self.metrics_collector.clone()
    }

    /// 获取自定义组件
    pub fn get_custom_component<T: std::any::Any + Send + Sync>(&self, name: &str) -> Option<&T> {
        self.custom_components
            .get(name)
            .and_then(|component| component.downcast_ref::<T>())
    }

    /// 发现服务实例
    pub async fn discover_services(&self, service_name: &str) -> ServiceResult<Vec<ServiceInstance>> {
        self.registry.discover(service_name).await
    }

    /// 选择服务实例（使用负载均衡）
    pub async fn select_service_instance(&self, service_name: &str) -> ServiceResult<Option<ServiceInstance>> {
        let instances = self.discover_services(service_name).await?;
        if instances.is_empty() {
            return Ok(None);
        }
        
        let selected = self.load_balancer.select(&instances);
        Ok(selected)
    }

    /// 获取指标信息
    pub async fn get_metrics(&self) -> ServiceResult<HashMap<String, f64>> {
        if let Some(ref metrics) = self.metrics_collector {
            // TODO: 实现从指标收集器获取指标的逻辑
            Ok(HashMap::new())
        } else {
            Ok(HashMap::new())
        }
    }

    /// 初始化指标收集
    async fn initialize_metrics(&self, metrics: Arc<dyn MetricsCollector>) -> ServiceResult<()> {
        // 注册基础指标
        let labels = std::collections::HashMap::new();
        
        metrics.register_metric(
            "rustcloud_requests_total",
            "Total number of requests",
            rustcloud_metrics::MetricType::Counter,
            labels.clone(),
        ).await?;

        metrics.register_metric(
            "rustcloud_request_duration_seconds",
            "Request duration in seconds",
            rustcloud_metrics::MetricType::Histogram,
            labels.clone(),
        ).await?;

        metrics.register_metric(
            "rustcloud_active_connections",
            "Number of active connections",
            rustcloud_metrics::MetricType::Gauge,
            labels,
        ).await?;

        info!("指标收集初始化完成");
        Ok(())
    }

    /// 启动健康检查服务器
    async fn start_health_check_server(&self) -> ServiceResult<()> {
        let port = self.config.network.health_port;
        let framework = self.clone(); // TODO: 实现Clone trait
        
        tokio::spawn(async move {
            // TODO: 实现健康检查HTTP服务器
            info!("健康检查服务器启动在端口: {}", port);
        });

        Ok(())
    }

    /// 启动指标服务器
    async fn start_metrics_server(&self) -> ServiceResult<()> {
        let port = self.config.monitoring.metrics.port;
        
        tokio::spawn(async move {
            // TODO: 实现指标HTTP服务器
            info!("指标服务器启动在端口: {}", port);
        });

        Ok(())
    }

    /// 启动管理控制台服务器
    async fn start_admin_server(&self, port: u16) -> ServiceResult<()> {
        tokio::spawn(async move {
            // TODO: 实现管理控制台HTTP服务器
            info!("管理控制台启动在端口: {}", port);
        });

        Ok(())
    }
}

// 为了支持在async块中使用，需要实现Clone
impl Clone for RustCloudFramework {
    fn clone(&self) -> Self {
        Self {
            config: self.config.clone(),
            registry: self.registry.clone(),
            load_balancer: self.load_balancer.clone(),
            circuit_breaker: self.circuit_breaker.clone(),
            metrics_collector: self.metrics_collector.clone(),
            custom_components: HashMap::new(), // 注意：自定义组件不能克隆
            service_instance: self.service_instance.clone(),
            state: self.state.clone(),
            lifecycle_manager: LifecycleManager::default(), // 生命周期管理器使用默认值
        }
    }
}